Deacetylation of chitin is closely related to insect development and metamorphosis. Chitin deacetylase (CDA) is a key enzyme in the process. However, to date, the CDAs of Bombyx mori (BmCDAs), which is a model Lepidopteran insect, were not well studied. In order to better understand the role of BmCDAs in the metamorphosis and development of silkworm, the BmCDA2 which is highly expressed in epidermis was selected to study by bioinformatics methods, protein expression purification and immunofluorescence localization. The results showed that the two mRNA splicing forms of BmCDA2, namely BmCDA2a and BmCDA2b, were highly expressed in the larval and pupal epidermis, respectively. Both genes had chitin deacetylase catalytic domain, chitin binding domain and low density lipoprotein receptor domain. Western blot showed that the BmCDA2 protein was mainly expressed in the epidermis. Moreover, fluorescence immunolocalization showed that BmCDA2 protein gradually increased and accumulated with the formation of larval new epidermis, suggesting that BmCDA2 may be involved in the formation or assembly of larval new epidermis. The results increased our understandings to the biological functions of BmCDAs, and may facilitate the CDA study of other insects.
Animals ; Bombyx/metabolism* ; Metamorphosis, Biological/genetics* ; Larva/metabolism* ; Gene Expression ; Insect Proteins/metabolism* ; Chitin

microRNAs (miRNAs) are an extensive class of -22-nucleotide (nt) endogenous noncoding RNAs regulating life activities ofmetazoans through binding to 3'-untranslated regions (3'-UTRs) of their target genes. This work aimed to identify yan gene in the silkworm, reveal its expression profile and confirm if it is one target of bmo-miR-7 and, as such, have potential for contributing to better understanding of the molecular mechanisms involved in the metamorphosis of silkworm. Based on homolog searching and PCR amplification, we cloned the coding sequence (CDS) of Bmyan, which encodes 476 amino acid residues and contains SAM-PNT and ETs domains. Quantitative PCR (q-PCR), RT-PCR and microarray data revealed high expression of Bmyan in the head, body wall and ovary of day-3 fifth instar larval silkworm, low or no expression in other tissues. It was lowly expressed in the early larval stages, but highly expressed from late spinning to day 4 pupa. The 3'-UTR of Bmyan was obtained by rapid-amplification of cDNA ends (3'RACE) and predicted to contain two potential recognition sites of bmo-miR-7. The luciferase reporter vector containing the 3'-UTR of Bmyan was constructed and co-transfected into BmE cell line with the mimic of bmo-miR-7 and the decreased relative activity of luciferase showed that Bmyan is one target of bmo-miR-7. This work helps further functional analysis of bmo-miR-7 and Bmyan in the silkworm.
3' Untranslated Regions ; Animals ; Bombyx ; genetics ; Cell Line ; Cloning, Molecular ; Female ; Genetic Vectors ; Insect Proteins ; genetics ; Larva ; Metamorphosis, Biological ; MicroRNAs ; genetics ; Pupa

The heterochronic genes regulate cell proliferation and switch development stage transitions. Heterochronic genes might also play important roles in regulating the development of silkworm, but very few of their expression profiles, functions and their relationship with microRNAs are available so far. Firstly, in this work, the primers for cloning Bmlin-41 were designed based on the homologous sequence of known Drosophila melanogaster lin-41, which was used as the query to blast against SilkDB. The obtained full CDS (2 166 bp) of Bmlin-41 encodes 721 amino acids and contains B-box and NHL domains. Then, the spatiotemporal expression patterns of Bmlin-41 were characterized by RT-PCR, quantitative real time PCR as well as our lab's previous silkworm genome microarray data. Bmlin-41 was increasingly expressed from embryonic to adult stage. In diverse tissues of day-3 fifth instar, Bmlin-41 showed the highest accumulation in ovary, secondly in testis and midgut, but very low expression was observed in other tissues. Finally, 3'UTR of Bmlin-41 1 434 bp was cloned by rapid-amplification of cDNA ends (3'RACE) and was predicted to bare two binding sites of bmo-let-7 by using online RNAhybrid. To verify the binding effect, 3'UTR was cloned into psi-CHECK-2 vector and submitted to dual luciferase assay in the S2 cells in vitro. The dual luciferase assay demonstrated that Bmlin-41 was down-regulated by bmo-let-7 mimics and upregulated by bmo-let-7 antagomir, thus confirming the Bmlin-41 is negatively regulated by bmo-let-7. Our work might help further study on the roles of Bmlin-41 and bmo-let-7 and their regulation relationship involved in controlling metamorphosis of silkworm.
3' Untranslated Regions ; Animals ; Bombyx ; Cloning, Molecular ; DNA, Complementary ; Down-Regulation ; Drosophila melanogaster ; Gene Expression Regulation ; Insect Proteins ; genetics ; metabolism ; Metamorphosis, Biological ; MicroRNAs ; metabolism ; Transcription Factors ; genetics ; metabolism

To study the role of the thyroid hormone receptor TRalphaA involved in the process of the metamorphic development of Japanese flounder, we firstly cloned the TRalphaA gene, then ligated into the fusion expression vector pET30a and expressed in Escherichia coli DE3 (BL21) host cells. After induced for 4 h with 1 mmol/L Isopropyl beta-D-Thiogalactoside, the target fusion protein was successfully expressed and identified in inclusion bodies by SDS-PAGE and Western blotting. The recombinant protein was denatured and purified by His-Bind resin, then renatured through gradient washing on His-bind resin column. After that, polyclonal antibody was prepared by immunizing New Zealand rabbits with purified protein. Dot blotting analysis showed the antibody with the titer of 1:200 000 reacted specifically to the expressed recombinant protein. Furthermore, a chromatin immunoprecipitation assay was performed to identify the specific binding between the antibody and TRalphaA in living cells of Japanese flounder. The result showed that thyroid hormone was involved in the alkaline phosphatase (ALP) gene transcriptional regulation through TRalphaA in vivo.
Alkaline Phosphatase ; genetics ; immunology ; Animals ; Antibodies ; immunology ; Escherichia coli ; genetics ; metabolism ; Flounder ; physiology ; Metamorphosis, Biological ; physiology ; Rabbits ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Thyroid Hormone Receptors alpha ; biosynthesis ; genetics ; immunology